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Diagnosis

Acne Inversa Diagnosis: How Does It Work?

How is acne inversa diagnosed? This overview explains the medical history, examination, typical criteria, possible additional questions and how to prepare well for the appointment.

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Last updated

Written by Dr. rer. nat. Dennis Alexander Kwiatkowski

60-second summary

If you only remember five things, remember these:

  • HS is diagnosed clinically: history and examination, not a single blood test or scan.
  • Three things carry most of the weight: typical lesions, typical locations and recurrence over time.
  • Clinicians also rule out look-alikes such as boils, folliculitis, abscesses and pilonidal sinus.
  • Severity is often described with the Hurley stages, which frame the treatment conversation.
  • Additional tests are used to check for other conditions, not to prove HS itself.

Because the diagnosis rests on a pattern, what you report about the past months often matters as much as what is visible on the day.

No test confirms HS. Early on, how the condition will progress can only be estimated, not predicted.

Before the appointment, write down where lesions appear, how often they return and how long each episode lasts.

Track symptoms and patterns

This summary is written and updated together with the full text. The evidence, limitations and sources stay unchanged in the article below.

Continue to the detailed explanation

The Short Answer

Acne inversa is usually diagnosed clinically. This means that medical professionals listen to your history, examine the skin and look out for a typical pattern.

A single blood test does not prove HS. Three questions are particularly decisive: Which lesions occur, where do they occur and do they keep coming back?

1. The Medical History

The conversation is not only about the current spot. Typical questions are:

  • How long have the symptoms been present?
  • Which areas of the body are affected?
  • How often do nodulesNodule: A firm, palpable lump deep in tissue. Nodules can be painful and may progress to abscesses. They are among the typical early signs of Acne Inversa., abscessesAbscess: An inflamed cavity or swelling containing pus or fluid. In hidradenitis suppurativa, abscesses can form as part of the inflammatory disease process and do not automatically mean that a bacterial infection is present. Secondary bacterial infection can occur and may require separate medical assessment. In Acne Inversa, abscesses occur mainly in the armpits, groin, and other skin folds. or weeping areas recur?
  • Do scars, hardened areas or recurring openings remain?
  • Which treatments or diagnoses have there been so far?

Pain, sleep, movement, work and feelings of shame are also part of the history, because they show how strongly the symptoms affect everyday life.

2. The Examination

During the examination, the focus is on which skin changes are currently visible. These may include deep nodules, abscesses, weeping areas, scars or tunnelsSinus Tract: A tunnel-like channel under the skin that forms between abscesses or nodules. Sinus tracts indicate more advanced disease and can chronically drain fluid. They are associated with Hurley Stages II and III. (sinus tracts).

The location helps with the assessment. Typical regions are the armpits, groin, genital and perineal region, buttocks and the skin folds under the breast. Other causes remain possible nonetheless.

3. The Clinical Assessment

HS becomes more likely when typical lesions in typical locations come together with a chronic or recurring course. This is precisely why the question “How often has this happened before?” is so important.

Depending on the findings, it is also checked which other explanations might fit, for example boilsBoil (Furuncle): Patient-community term for an inflammatory nodule or abscess. Important caveat: an ordinary single boil (furuncle) is a one-off bacterial hair-follicle infection. The recurring, multifocal 'boils' of Acne Inversa are not the same thing — this misdiagnosis is a main reason HS goes unrecognised for years., folliculitis, inflamed cysts, acne or a pilonidal sinus.

4. Additional Tests, When They Make Sense

Not every appointment requires the same tests. Depending on the situation, swabs, laboratory values, imaging or further specialist assessment may be helpful. Such steps can better classify complications, accompanying conditions or other causes.

However, they do not replace the clinical assessment of the disease course.

5. What You Can Prepare

A brief overview often helps more than a perfect wording:

  1. Note the body areas and how often symptoms occur.
  2. Bring photos of active spots, if available.
  3. Gather earlier treatments, procedures and diagnoses.
  4. Openly address scars, dischargeDischarge / Exudate: Fluid coming from an Acne Inversa lesion or tunnel. Can be clear (serous), bloody (sanguineous), pus-like (purulent), or a mix., concerns about odour and pain.
  5. Write down questions that you do not want to forget during the appointment.

If not everything is resolved at the first appointment, that is not a failure. A good diagnosis emerges from examination, the course of the disease and a conversation that takes the recurring pattern seriously.

Terms explained in this article

Quick definitions of the key medical terms. Select any term for its full glossary entry.

Nodule
A firm, palpable lump deep in tissue. Nodules can be painful and may progress to abscesses. They are among the typical early signs of Acne Inversa.
Abscess
An inflamed cavity or swelling containing pus or fluid. In hidradenitis suppurativa, abscesses can form as part of the inflammatory disease process and do not automatically mean that a bacterial infection is present. Secondary bacterial infection can occur and may require separate medical assessment. In Acne Inversa, abscesses occur mainly in the armpits, groin, and other skin folds.
Sinus Tract
A tunnel-like channel under the skin that forms between abscesses or nodules. Sinus tracts indicate more advanced disease and can chronically drain fluid. They are associated with Hurley Stages II and III.
Boil (Furuncle)
Patient-community term for an inflammatory nodule or abscess. Important caveat: an ordinary single boil (furuncle) is a one-off bacterial hair-follicle infection. The recurring, multifocal 'boils' of Acne Inversa are not the same thing — this misdiagnosis is a main reason HS goes unrecognised for years.
Discharge / Exudate
Fluid coming from an Acne Inversa lesion or tunnel. Can be clear (serous), bloody (sanguineous), pus-like (purulent), or a mix.

References

  1. North American clinical management guidelines for hidradenitis suppurativa, Part I Journal of the American Academy of Dermatology, 2019
  2. S2k Guideline for the Therapy of Hidradenitis suppurativa / Acne inversa AWMF, 2024
  3. Diagnosis of Hidradenitis suppurativa Centre de Preuves en Dermatologie, 2026